ceph/src/rocksdb/java/src/main/java/org/rocksdb/SkipListMemTableConfig.java

   1 // Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
   2 package org.rocksdb;
   3
   4 /**
   5  * The config for skip-list memtable representation.
   6  */
   7 public class SkipListMemTableConfig extends MemTableConfig {
   8
   9   public static final long DEFAULT_LOOKAHEAD = 0;
  10
  11   /**
  12    * SkipListMemTableConfig constructor
  13    */
  14   public SkipListMemTableConfig() {
  15     lookahead_ = DEFAULT_LOOKAHEAD;
  16   }
  17
  18   /**
  19    * Sets lookahead for SkipList
  20    *
  21    * @param lookahead If non-zero, each iterator's seek operation
  22    *     will start the search from the previously visited record
  23    *     (doing at most 'lookahead' steps). This is an
  24    *     optimization for the access pattern including many
  25    *     seeks with consecutive keys.
  26    * @return the current instance of SkipListMemTableConfig
  27    */
  28   public SkipListMemTableConfig setLookahead(final long lookahead) {
  29     lookahead_ = lookahead;
  30     return this;
  31   }
  32
  33   /**
  34    * Returns the currently set lookahead value.
  35    *
  36    * @return lookahead value
  37    */
  38   public long lookahead() {
  39     return lookahead_;
  40   }
  41
  42
  43   @Override protected long newMemTableFactoryHandle() {
  44     return newMemTableFactoryHandle0(lookahead_);
  45   }
  46
  47   private native long newMemTableFactoryHandle0(long lookahead)
  48       throws IllegalArgumentException;
  49
  50   private long lookahead_;
  51 }